Leaky gut is just as it sounds. A damaged small intestine lining (damaged by grains, legumes, and dairy) that allows food particles, toxins, wastes and proteins to enter the blood stream causing a autoimmune reaction. I like how Dr. Sarah Ballantyne PhD explains leaky gut and the Autoimmune Protocol and think that she does a fantastic job explaining the aspects in detail so I will link her resources down below. After the allergens and irritants are eliminated from the diet the gut can begin to heal. Once healed, these eliminated foods can be added back in slowly to see which can be tolerated and which cannot.This whole process can take anywhere from 6 months to 2 or more years.